There are two main categories of birthmarks.Red birthmarks are made up of blood vessels close to the skin surface, and are called vascular birthmarks.Pigmented birthmarks are areas in which the color of the birthmark is different from the color of the rest of the skin.

Hemangiomas are a common vascular birthmark. Their cause is unknown. The color results from the development of blood vessels at the site.

Cafe-au-lait spots may occur in people with the genetic disorder, neurofibromatosis.

Nearly everyone has moles, which usually appear after birth.

Mongolian spots are more commonly seen in darker-skinned populations.Symptoms

Each type of birthmark has its own appearance:Cafe-au-lait spots are light tan, the color of coffee with milk.Moles are small clusters of colored skin cells.Mongolian spots (also called Mongolian blue spots) are usually bluish or bruised-looking. They usually appear over the lower back or buttocks, but can also appear in other areas, including the trunk or arms.

Newborn infants can become infected with herpes virus:In the uterus (intrauterine herpes -- this is very rare)Passing through the birth canal (birth-acquired herpes, the most common method of infection)Right after birth (postpartum) from kissing or having other contact with someone who has herpes mouth sores

If the mother has an active genital herpes infection at the time of delivery, the baby is more likely to become infected during birth. Some mothers may not be aware they have internal (inside the vagina) herpes sores.

Some people have had herpes infections in the past, but were not aware of it. These people, not knowing that they have herpes, may pass it to their...

Bipolar disorder affects men and women equally. It usually appears between ages 15 - 25. The exact cause is unknown, but it occurs more often in relatives of people with bipolar disorder.

Types of bipolar disorder:People with bipolar disorder type I have had at least one fully manic episode with periods of major depression. In the past, bipolar disorder type I was called manic depression.People with bipolar disorder type II have never experienced full-fledged mania. Instead they experience periods of hypomania (elevated levels of energy and impulsiveness that are not as extreme as the symptoms of...

Biliary stricture

A biliary stricture is an abnormal narrowing of the common bile duct, the tube that moves bile (a substance that helps with digestion) from the liver to the small intestine.Alternative Names

Bile duct strictureCauses, incidence, and risk factors

A biliary stricture is often caused by surgical injury to the bile ducts. For example, it may occur after surgery to remove the gallbladder.

Other causes of this condition include:Cancer of the bile ductDamage and scarring due to a gallstone in the bile ductPancreatitisPrimary sclerosing cholangitis

Risk factors include previous biliary surgery, pancreatitis, gallstones, or injury to the intestine.SymptomsAbdominal painChillsFeverItchingJaundiceNausea and vomitingPale or clay-colored stoolsSigns and tests

The following tests can help diagnose this condition:Endoscopic retrograde cholangiopancreatography (ERCP)Percutaneous...

Biliary atresia

Definition

Biliary atresia is a blockage in the tubes (ducts) that carry a liquid called bile from the liver to the gallbladder. The condition is congenital, which means it is present from birth.Causes, incidence, and risk factors

Biliary atresia occurs when the bile ducts inside or outside the liver do not develop normally. It is not known why the biliary system fails to develop normally.

The bile ducts help remove waste from the liver and carry salts that help the small intestine break down (digest) fat.

In babies with biliary atresia, bile flow from the liver to the gallbladder is blocked. This can lead to liver damage and cirrhosis of the liver, which is deadly if not treated.Symptoms

Newborns with this condition may appear normal at birth. However, jaundice (a yellow color to the skin and mucous membranes) develops by the second or third week of life. The infant may gain...

Bile is a liquid released by the liver. It contains cholesterol, bile salts, and waste products such as bilirubin. Bile salts help your body break down (digest) fats. Bile passes out of the liver through the bile ducts and is stored in the gallbladder. After a meal, it is released into the small intestine.

When the bile ducts become blocked, bile builds up in the liver, and jaundice (yellow color of the skin) develops due to the increasing levels of bilirubin in the blood.

The possible causes of a blocked bile duct include:Cysts of the common bile ductEnlarged lymp nodes in the porta hepatisGallstonesInflammation of the bile...

Bilateral hydronephrosis

Bilateral hydronephrosis is the enlargement (distention) of the urine collecting structures and pelvis of both kidneys. Bilateral means both sides.

See also: Unilateral hydronephrosisAlternative Names

Hydronephrosis - bilateralCauses, incidence, and risk factors

Bilateral hydronephrosis occurs when urine is unable to drain from the kidney down the ureters into the bladder. Hydronephrosis is not itself a disease, but rather a physical result of whatever disease is keeping urine from draining out of the kidneys, ureters, and bladder.

Bicuspid aortic valve

A bicuspid aortic valve is an aortic valve that only has two leaflets, instead of three.

The aortic valve regulates blood flow from the heart into the aorta, the major blood vessel that brings blood to the body.Alternative Names

Bicommissural aortic valveCauses, incidence, and risk factors

The aortic valve allows oxygen-rich blood to flow from the heart to the aorta. It prevents the blood from flowing back from the aorta into the heart when the pumping chamber relaxes.

Bicuspid aortic valve is present at birth (congenital). An abnormal aortic valve develops during the early weeks of pregnancy, when the baby's heart develops. The cause of this problem is unclear, but it is the most common congenital heart disease. It often runs in families.

The bicuspid aortic valve may not be completely effective at stopping blood from leaking back into the heart. This is called aortic...

Bezoar

A bezoar is a ball of swallowed foreign material (usually hair or fiber) that collects in the stomach and fails to pass through the intestines.Alternative Names

Trichobezoar; HairballCauses, incidence, and risk factors

Chewing on or eating hair or fuzzy materials (or indigestible materials such as plastic bags) can lead to the formation of a bezoar. The rate is very low and the risk is greater among mentally retarded or emotionally disturbed children. Generally bezoars are mostly seen in females aged 10 to 19.SymptomsIndigestionStomach upset or distressNauseaVomitingDiarrheaPainGastric ulcersSigns and tests

The child may have a lump in the abdomen that can be felt by the health care provider. A barium swallow x-ray will show the mass in the stomach, sometimes a scope is used (endoscopy) to directly view the bezoar.Treatment

Beriberi

There are two major types of beriberi:Wet beriberi affects the cardiovascular system.Dry beriberi and Wernicke-Korsakoff syndrome affect the nervous system.

Beriberi is rare in the United States because most foods are now vitamin enriched. If you eat a normal, healthy diet, you should get enough thiamine. Today, beriberi occurs mostly in patients who abuse alcohol. Drinking heavily can lead to poor nutrition, and excess alcohol makes it harder for the body to absorb and store thiamine.

A rare condition known as genetic beriberi is inherited (passed down through families). People with genetic beriberi lose the ability to absorb thiamine from foods. This can happen slowly over time and symptoms...